Science & Technologies Volume II, Number 1, 2012 Medicine 236                      !  "# ""    $%#    &&’ (  " ’’ )   $%# )                 ! "#   $!  % &  ’ (  )*+ #!#,*-. * Epidemiological investigations during the last decades have proven that the cutaneous malignant melanoma is a complex disease. There are variety of genetic and environmental factors and their interactions which are implicated in the developments of this neoplastic disease. The enhanced ultraviolet exposure (UV) is considered as the most important environmental factor contributing to skin melanoma. It has been fund that UV light has a pleiotropic effect on the skin cells, which includes both direct damage of DNA due to formation of pyrimidine (thymine) dimmers and indirect effect via generation of reactive oxygen species (ROS). In this respect the gene variants in enzymes involved in detoxification of the oxidative stress products are considered as important factors influencing the risk for development of cutaneous malignant melanoma and other types of skin cancers promoted by UV exposure. GSTT1 and GSTM1 are isoenzymes of the large family of glutathione1S1transferases, expressed in the skin and able to detoxify products of oxidative stress reactions caused by UV irradiation. The aim of the current study was to examine the relation of GSTM1 and GSTT1 null polymorphisms with skin malignant melanoma risk in a pilot case1control study of Bulgarian patients and unaffected controls. A modified multiplex (duplex/triplex) PCR1based method was applied for detection of GSTs’ genotypes. Our results showed no statistically significant difference between melanoma patients and healthy controls in the frequency of null GSTM1 genotype (p=0.505, χ21test). However there was a tendency for increased risk for melanoma in carriers of /’ null genotype (p=0.107, χ21test), especially among the females who appeared to have more than five time higher risk than the women with non1null /’ genotype (OR=5.60, 95% CI, 1.54120.43, p=0.014, Fisher’s exact test). Our current results suggest that the inherited absence of GST1theta, but not of GST1mu detoxifying enzymes due to the presence of homozygous null genotypes may be associated with skin malignant melanoma, especially in women.   !   /’ /’     +,&$ The skin malignant melanoma is a neoplastic disease which is developed during the tumor transformation f epidermal melanocytes. During the last two decades there is worldwide a stable tendency for significant increase of the cutaneous melanoma cases (Balch, Soong et al. 1983; Barth, Wanek et al. 1995; Brand, Ellwanger et al. 1997; Kamangar, Dores et al. 2006). Today, more than 350 new cases and more than 120 deaths of melanoma are registered each year in Bulgaria (Valerianova, Vukov et al. 2008). Epidemiological investigations during the last decades have proven that the cutaneous malignant melanoma is a complex disease. There are variety of genetic and environmental factors and their interactions which are implicated in the developments of this neoplastic disease. The most important are considered those related to the behavior during exposure to sun light and the genetic determinants of the skin features and complexion (Elwood 1996; Gandini, Sera et al. 2005; Dennis, Vanbeek et al. 2008; Chang, Barrett et al. 2009). The enhanced ultraviolet exposure (UV) is